Hey guys, if there is already a post about this question please let me know, I tried looking but couldn't find it. I'm trying to trade my civic for my dad's Jeep but the only thing holding him back is this problem he's having with it.

My dad has an 02 Grand Cherokee Limited 4.7 full time AWD, and he's saying that there is a whining or howling as speed increases but not with the engine. At one point when he had it serviced, the dealership thought it might be the front differential. They also said that this would be common. Can anyone verify this and if so does anyone know what could cause this/fix this? Any help would be much appreciated.

Abuse or lack of proper maintenance can cause a bad front differential. It could also be due to using the wrong fluid and there could be something wrong with the Varilok diff, although I don't think that would cause a howling sound. It could also be a bad wheel bearing. Whatever you find is broken, the fix is replacing the broken part. Might sound like a dumb answer, but maybe you should consider the question (what could fix a bad front differential? A new one!)

Best of luck. And I would recommend an independent shop over the dealer any day of the week. Dealer techs are all about doing warranty service on the new models and not about taking care of older out-of-warranty rigs. Their primary goal is to do the job as quickly as possible and it seems to me like they are just guessing at the problem. "It might be..." is not the answer you want from a professional tech. "It is..." is the answer you are looking for.

My Wj did this when i had the NV247. Ive recently just swapped to a 242. It has nothing to do with your transfer case. The problem or noise your probably hearing if it isnt a wheel bearing is probably your pinion bearing in the front diff. Does it only do it while your foot is on the gas? Or Slowing down. Being the its "AWD" it always has a good amount of pressure on the Front DS when your foot is on the gas or when you are braking. Pinion bearing replacement is most likely something to take to a garage. Also check your CV boots for tears and what not. Good luck!

I hope I'm conveying this correctly. He said it didn't matter if he were on the gas or not, that if he were at speed and let off it was the same.

I appreciate the replies, I know the one question was kind of dumb, if something's broke, fix it! I looked into the parts for replacing the potentially broke stuff was only going to run me about $500-600 if I were to replace it all.

You might also consider a used axle assembly. Granted you don't know for sure what you are going to get, but you can DIY an axle swap in an afternoon pretty easily and a lot of places offer warranties on their used parts. It's an option that is probably a bit cheaper and easier than rebuilding the whole front diff.

I hope I'm conveying this correctly. He said it didn't matter if he were on the gas or not, that if he were at speed and let off it was the same.

I appreciate the replies, I know the one question was kind of dumb, if something's broke, fix it! I looked into the parts for replacing the potentially broke stuff was only going to run me about $500-600 if I were to replace it all.